1. Field of the Invention
The invention is related to the field of magnetic disk drive systems and, in particular, to fabricating a magnetic write pole in a recording head of a magnetic disk drive system.
2. Statement of the Problem
Many computer systems use magnetic disk drives for mass storage of information. Magnetic disk drives typically include one or more magnetic recording heads (sometimes referred to as sliders) that include read elements and write elements. A suspension arm holds the recording head above a magnetic disk. When the magnetic disk rotates, an air flow generated by the rotation of the magnetic disk causes an air bearing surface (ABS) side of the recording head to ride a particular height above the magnetic disk. The height depends on the shape of the ABS. As the recording head rides on the air bearing, an actuator moves an actuator arm that is connected to the suspension arm to position the read element and the write element over selected tracks of the magnetic disk.
A typical write element includes write pole and a return pole. The write pole has a yoke portion and a pole tip portion. The pole tip extends from the ABS of the recording head to the yoke of the write pole. The point where the pole tip meets the yoke is referred to as the flare point. This point where the yoke begins has a trapezoidal shape that flares outwardly from the pole tip. The yoke of the write pole then connects to the return pole through a back gap. A coil wraps around a yoke or back gap to provide the magnetic flux used for the write operation. The width of the pole tip controls the track width that is written by the recording head, so the width of the pole tip is preferably small (i.e., less than 100 nanometers).
It is a problem with present fabrication techniques to fabricate a pole tip having smaller widths, such as less than about 70 nanometers. A pole tip is typically defined using a photo-lithographic process to pattern a photo-resist. An etching process is then performed to define the pole tip based on the pattern of the photo-resist. Unfortunately, if a photo-resist is sufficiently thin, such as less than 70 nanometers, the photo-resist does not hold its shape and does not adequately provide a mask for an etching process used to define the pole tip. Thus, the width of the pole tip is limited by the tolerances of photo-lithography, which may not be small enough for high density recording. Similarly, an additive process has lithographic restrictions where the width of the final pole has the same tolerances.